using System.Threading.Tasks;
using UnityEngine;
using static UnityEditor.PlayerSettings;

public class Target : MonoBehaviour
{
    public BoxCollider targetMoveAbleArea;
    public LayerMask hitMask;
    public float moveSpeed = 1;
    public float rotateSpeed = 1;
    private Vector3 targetPos;
    private void Awake()
    {
        RandomSpawn();
    }
    //private void Update()
    //{
    //    if (Input.GetKeyDown(KeyCode.F))
    //    {
    //        RandomSpawn();
    //    }
    //}

    private void FixedUpdate()
    {

        var dir = targetPos - this.transform.position;
        if (dir.magnitude > .5f)
        {
            var targetRot = Quaternion.LookRotation(dir, Vector3.up);
            this.transform.rotation = Quaternion.Slerp(this.transform.rotation, targetRot, Time.fixedDeltaTime * rotateSpeed);
            this.transform.position += this.transform.forward * moveSpeed * Time.fixedDeltaTime;
        }
        else
        {
            SearchRandomTargetMovePos();
        }
    }

    private void SearchRandomTargetMovePos()
    {
        GetRandomPosition(out var tmpPos);
        var randomMoveOffset = (tmpPos - this.transform.position).normalized * moveSpeed;
        if (!Physics.BoxCast(this.transform.position, .5f * Vector3.one, randomMoveOffset, this.transform.rotation))
        {
            targetPos = tmpPos;
        }
    }

    private void RandomSpawn()
    {
        GetRandomPosition(out var pos);
        this.transform.position = pos;
        targetPos = pos;
    }

    private void GetRandomPosition(out Vector3 pos, int limit = 100)
    {
        pos = Vector3.one;
        if (limit < 0)
            return;
        var minPos = targetMoveAbleArea.bounds.min;
        var maxPos = targetMoveAbleArea.bounds.max;

        float randomF()
        {
            return Random.Range(0, 1.0f);
        }
        pos.x = Mathf.Lerp(minPos.x, maxPos.x, randomF());
        pos.y = Mathf.Lerp(minPos.y, maxPos.y, randomF());
        pos.z = Mathf.Lerp(minPos.z, maxPos.z, randomF());

        var hits = Physics.OverlapBox(pos, .5f * Vector3.one, Quaternion.identity, hitMask, QueryTriggerInteraction.Collide);
        if (hits.Length > 0)
        {
            GetRandomPosition(out pos, --limit);
        }
    }

    private async void DebugR()
    {
        int i = 1000;
        while (--i > 0)
        {
            GetRandomPosition(out var pos);
            var cube = GameObject.CreatePrimitive(PrimitiveType.Cube);
            cube.transform.position = pos;
            await Task.Yield();
        }

    }
}